Battery warning light stays on

[Blacky50]

The battery warning light stays on even when the engine is running. I tested the voltage at the cigarette lighter. Engine off 12.6v, engine running 14.2v. From that I deduce that the alternator is charging.
Also various electrical components have stopped working - indicators & hazard lights, heater blower, electric windows and possibly more not tested. Other components are still working - lights, horn & interior lights.
No fuses are blown in the passenger fuse board under the steering wheel.
It’s a 2001 Multispace Diesel 1.9 litre.
Any ideas on what it might be & how to fix it?
Thanks

[brodfather11]

did you check the engine fuse box fuses ?, it is involved with the supply for most of the items you mentioned and supplies the interior fuse box . if a fuse in the engine fuse box is blown it wont show as a fuse blown in the interior box.

[Sol]

There are also hidden main fuses under the top layer in the engine bay fusebox.

[Blacky50]

I’ve now checked all of the engine fuse box fuses and they are all intact. (Not the hidden ones - how do I get to those?)

[Blacky50]

So it looks like I have solved it. I disconnected the battery -ve first, left it for 30 minutes, then reconnected +ve first. Then after starting the engine, the components that weren’t working now are.
Strange, but I guess something to do with the BSI.

[Sol]

Sounds good, often does the trick. The hidden fuses btw are under the top tray of the engine fusebox, which is usually rivetted in place and are marked Citroen access only in the diagrams. But they are still just large fuses.